| 摘要 |
PROBLEM TO BE SOLVED: To provide a punching punch with which punching is performed by small and constant punching force by performing shearing so as to be gradually progressed while keeping a shear angle when punching the side face of a metallic pipe, and to provide a punching method using the same. SOLUTION: The punch for punching the side face of the pipe is characterized in that two inner edges 7, 8 formed with pointed tip parts 5, 6 in two opposite positions on the circumference of the punch 1 respectively and composed of continuous curved surfaces inclined toward the inside of the punch 1 from both tip parts 5, 6 are formed convexly toward the base part of the punch 1 and two lines 11, 12 of intersection formed with two inner edges 7, 8 form a prescribed angle to the axis of the punch 1. The punching method for the pipe is also provided by which punching is performed by driving this punch 1 into the side face of the pipe. COPYRIGHT: (C)2006,JPO&NCIPI
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